Convertible graphic press

ABSTRACT

The subject-matter of this invention is a sturdy but knock-down graphic press having a basic frame and bed with interchangeable parts for quick and easy conversion from a lithographic press to an intaglio and relief printing press without in any way compromising the quality of printmaking regardless of the type of print. The press is so constructed that it can be assembled and disassembled easily and quickly with a minimum of tools, and no special ones, making portability a high priority factor. The press has the full capabilities of producing the best in lithography as well as in intaglio and relief printing.

CONVERTIBLE GRAPHIC PRESS BACKGROUND FOR THE INVENTION For many yearsthe printmaker has been required to use two different types of printpresses regardless of size, one for printing lithographs and another foretchings, woodcuts,.linoleum cuts and wood engravings. The same type ofpress could be used for intaglio printing (etching) as well as forrelief printing from blocks but not for lithography. Since presses areexpensive and usually represent a lifetime investment, the printmakerhad to make a choice and commit his efforts to a single type of work.Accordingly, there has long been an effort to produce a press whichcould be satisfactorily and quickly converted from one form of printingto the other and vice verse so that this choice of effort could beeliminated. Of course the time factor is important and the change-overshould be fast and simple. There have been several forms of combinationpresses devised which could be adapted to perform all three conventionalprinting operations. However, so far is known, all have failed for onereason or other but principally on the basis of the failure toaccomplish interchangeability easily and effectively, withoutcompromising the printing results for the standard and conventionalprinting operations.

Recently, there has been a definite up-surge in the printmakers art andthe demand for adequate presses has not kept up with the resurgence ofthe demand.

The graphic press disclosed and described herein was conceived with theover all objectives of providing a press which was fully interchangeablewithout any compromise due to the interchangeability, and thereforefunctional to produce the best of lithography and the best of intaglioand relief printings.

In the prior art, the interchangeability attempted has forcedcompromises from many directions. One is in roller size. Intaglioprinters believe, as the result of long experience, that a large rolleris much superior to a small one. In the conversions of the prior art thesize of the roller was restricted to undersized dimensions. Another isthe pressure adjustment to the roller. In most instances the means andmethod for pressure adjustments are extremely limited and lead to faultyconstruction. And still another is the roller drive. Since bothlithography and intaglio presses, when converted employ the identicalframe, the two printing mechanisms required, together with their drives,may be quite different, and caused severe and destructive compromises inthe interchangeably of mounting them on the same frame. However, theconstruction of this press permits the same drive for the intaglioprinting if desired without compromising the nature or quality of theresults. Each of these compromises as well as any compromise leads toinferior results so far as the operation of the press is concerned, withresulting inferior prints.

SUMMARY OF THE INVENTION The present graphic press is truly anall-around graphic art press. It provides all of the requirements forintaglio printing and relief printing and is readily converted toprovide the best features of lithography. It is a sturdy press,constructed of hollow steel members for lightness in weight withoutcompromising in strength, and suitably braced so that the stresses andpressures of all types printing will not be disturbed or distorted byundue flexing and orother movement. In addition the graphic pressdisclosed is portable as well as demountable. It does not rely on theflimsy construction required for folding but can be assembled ordisassembled and transported by one or two persons using only twospanner and two Allen wrenches. Since any material will bend underprinting pressure, unless prevented, the present invention provides arigid central drum which is solid to take any pressures involved. Furthermore there is no waste of weight or cost in trying to make the bedstiff. Contrary to everything shown in the art the bed is flexibleenough so that any warpage will easily be flatten during the printing.

One of the great advantages in the interchangeability of the equipmentto meet the specific requirements of lithography on one hand andintaglio on the other, is that the press of this invention uses a largeroller, i.e., nine inches in diameter, such are employed on a singlepurpose etching press. This is accomplished by complete removability ofthe lithography mechanism of the bridge. There would be no room for anine inch roller where any of the lithographing mechanism was retainedto support the intaglio mechanism. Many intaglio printers prefer thatthe top roller be driven. In this device two points are incorporatedfrom which the' drive crank may be attached. One to drive the bottomroller as in lithography, and the other to drive the intaglio roller,just as the printmaker prefers.

Further objects are to provide a construction of maximum simplicity,economy and ease of assembly and disassembly, also such further objects,advantages and capabilities as will fully appear and as are inherentlypossessed by the device and invention described herein. The inventionfurther resides in the combination, construction and arrangement ofparts illustrated in the accompanying drawings, and while there is showntherein a preferred embodiment thereof, it is to be understood that thesame is illustrative of the invention and that the invention is capableof modification and change and comprehends other details of constructionwithout departing from the spirit thereof or the scope of the appendedclaims.

BRIEF DESCRIPTION OF THE DRAWINGS:

FIG. 1, is a perspective view of the graphic press set up forlithography;

FIG. 2, is a perspective view of the same press set up for intaglio andrelief printing;

FIG. 3, is a fragmentary view partly in longitudinal section and partlyin elevation taken on the line III-III of FIG. 1; i

FIG. 4, is a fragmentary transverse section taken on the line IV IV ofFIG. 1;

FIG. 5, is a schematic view of a possible power drive;

FIG. 6, is a fragmentary transverse section and elevation taken ontheline Vl-VI of FIG. 1, and

FIG. 7, is a fragmentary transverse section and elevation taken on theline VII-VII of FIG. 2.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring now more particularly tothe drawings and with particular reference to FIGS. 1 and 2, the framefor the press is constructed so that it is sturdy yet light in weightand yet implementing the fundamental concept of its knockdownportability. While these concepts may appear to be in conflict, they areactually unexpectantly in a harmonious relationship in the presentconstruction. The frame is constructed of side bars 12 and 14 which arerectangular section tubing. Just beyond the mid point of the side barsand right angles thereto, the parallel vertical posts 15a, 15b, 16a, and161; are welded in position or secured in any other suitable manner.These vertical posts are equally spaced from each other and extend bothabove and below the side bars 12 and 14. The bottom ends are connectedby spacers 17 and 18 which are secured in position in any suitablemanner, such as welding. Spaced a short distance from post 16b is ashorter post 19, which is preferably welded to side bar 14. The post 19may be eliminated if the drive is to be only on the under roller as willbe described later. The side bars 12 and 14 are provided with internallyextending flanges 20 and 21 which are intended to be flush with thebottom surface thereof and are ground to a smooth, level top surface, toform a track for the level and smooth passage of the bed, as hereinafterdescribed, with the side bars 12 and 14 forming the precision guides.Stops 22 are provided to limit the travel and prevent the bed frominadvertently falling or running off the track.

i The front legs are a pair of V-shaped members 23 and 24 also ofrectangular section tubing welded to- 'gether at the bottom or apex 25,together with an inturned foot plate 26. These legs are secured to theside bars under the front portion at either side, legs 23 being securedto the frame members 12 and 14 spaced inwardly from the beginning endsthereof, and leg members 24 being secured to the vertical posts 15a and16a respectively. The rear legs are also V-shaped, joined at the apex 27by welding or in any suitable manner, with an in-turned foot plate 28.Leg members 30 are secured to the vertical posts 15b and 16b and legmembers 31 are secured to side bars 12 and 14, adjacent rearward endsthereof. It thus appears that rail 12, vertical posts 15a and 15b andspacer 17 plus the secured leg members constitute a unitary section ofthe press, as does its complimentary substantially identical section atthe opposite side. Between the legs 23 in the front a spacer brace 32 isbolted which determines the width of the press and the amount ofseparation between the side bars 12 and 14. Cross bracing 33 and 34 isbolted to the leg members 24 to maintain the spacing and to give thestructure rigidity. Likewise, cross-bracing 35 and 36 is bolted betweenrear legs 31 to maintain the rigidity and spacing at the rear of thepress. It will be observed that by unbolting the cross bracing andspacing members 32, 33, 34, 35, and 36, then unbolting the leg members23 and 24, 30 and 31 from the side bars 12 and 14 and posts 15a and 16a,the whole press frame can be disassembled quickly, and just as quicklyreassembled.

Assembly and disassembly can be accomplished in about one hour by twomen and any man can easily carry any of the 'parts. The entire presstherefore can be transported in a station wagon. The use of rectangularsection tubing for the side bars and legs give unexpected lightness andyet complete rigidity.-

The bed for the press, generally designated 37, is constructed of twosections of laminated fir 38, of substantial thickness in order toprovide elasticity under pressure but without distortion. The bed padcomprises a layer of neoprene 40, topped by a galvanized steel sheet 41which is turned down into a flange at its marginal edges to confine theneoprene sheeting 40. At its front marginal edge the bed 37 is suitablymounted on rollers 42 which travel on the flanges 20 and guide againstthe inner faces of the side bars 12 and 14. This insures smooth, leveltravel for the bed 37, without cocking or canting. -1 Also at the outermarginal edge of the bed bracket 43 may be provided which is an outerstop for the bed 37. To this bracket 43 may be secured a hand grip 44 tomanually move the bed 37 back and forth on the guide rails 20.

The pressure drum 45 is solid steel with axial stub shafts 47 which fitinto self-aligning ball bearings 46. These bearings 46 are mounted ateither side between the posts 15a and 15b and between posts 16a and 16babove the spacers 17 and 18 in such a manner as to permit the pressureroller 45 to bear directly against under surface of the bed 37 when itis in level traveling position. This is perhaps best shown in FIG. 3. Asthe bed 37 passes from left to right resting on the pressure cylinder45; the outer end is supported by guide wheels 48 mounted on the innerfaces of the end legs 31.

A boss 50, is welded to the vertical post 16a above the lbed and on theouter forward face thereof. The boss 50 is bored transversally as at 51to support a sprocket wheel 52 which rotates on a stub shaft journalledwithin the bore 51 in the conventional manner. This sprocket 52 isturned manually by hand crank 53. A chain 54, connects sprocket wheel55, with sprocket wheel 52. The sprocket wheel 55, is splined to theouter end of the stub shaft 47, on the roller 45, so that by turning thehand crank 53, the pressure roller 45, is likewise turned to move thebed in either direction, forward or backward, depending upon thedirection of the rotation of the hand crank 53.

It is a simple matter to convert the movement of the press from handoperation to motor operation as will be observed by reference to FIG. 5.A spacer bar 56 may be added between rear legs 30 for the mounting of amotor bracket 57 thereon. The motor 58, drives the sprocket 60 throughchain 61 to sprocket 5S. Adjacent the bed 37, along its right marginaledge is mounted a trip 62, which engages a contact 63, electricallycoupled to the power input for the motor to shut it off when the trip 63is activated. This would prevent the driving of the bed inadvertentlyoff of the rails at the back end.

Another feature of the equipment is shown in FIG. 3, and also in FIG. 1.Welded to the forward faces of posts 15a and 16a are bosses 64.Journalled in these bosses is a transverse rotating shaft 65. The shaftis rotated by means of hand lever 66. Secured on the shaft and under thebed 37, are spaced rollers 67. When the hand lever 66 is in the downposition, shown in full lines on FIG. 3, the rollers are completely outof operative engagement with the undersurface of the bed 37. As the handlever 66 is moved upwardly the wheels 67 engage the underside of the bed37, and raise it out of contact with the drive roller 45, so that thebed will then roll freely on its own rollers '42 and on the rollers 67and by use of the hand grip 44 can be rolled back and forth without thenecessity of turning the hand crank 53. This is a great convenience andtime saver.

Up to this point the entire press is identical whether used forlithography, intaglio printing or block printing. FIGS. 1, 3, and 6 showthe press as set-up for lithography. In the lithographic set-up, alithograph stone 70 is shown in its position on the press bed 37. On theinner opposed faces of the vertical posts 15a and 15b, and 16a and 16b,are integral guides 71. These guides function to receive interchangeableportions for both lithograph and for intaglio pinting and arecoextensive with the height above the side rails 12 and 14. The scrapperbox 72 stretches between the two sets of posts 15 and 16 and guides ateither end in the bearing guides 71. The scrapper 73 is attached to box72 on the undersurface thereof for contact with the tympan covering thematerial on the lithograph stone 70 during the printing process. Thepressure is applied by a yoke which is generally designated 74. The yokeconsists of two parallel sheets of steel 75. They are spaced from eachother by end spacers 76 and by spring anchors 77. Secured at the centralportion between two plates 75 is a bored cylindrical member 78 in whichthe plunger 80 guides for vertical passage. The plunger 80 is threadedaxially towards its lower end to receive the threaded adjusting screw 81which is rotated by the adjusting hand wheel 82. The hand wheel 82 has abearing portion 83 which exerts pressure on the scrapper box 72 inaccordance with the given adjustment. The plunger also carriestransverse wings 89 which bear against leaf springs 84, which in turnare anchored at their outer ends in any suitable manner to the springanchors 77. The plunger 80 at its top end carries a rotary cam followersurface which it can either be rotating as shown FIG. 6, or just a plainhemispherical or formed surface 85. A hand lever for exerting thepressure which is number 86, is eccentrically rotated around a pivotpoint 87, which is secured between the two yoke plates 75. The eccentric88 of the lever arm when bearing against the cam surface 85, forces theplunger downwardly in any increment desired. The four vertical posts15a, 15b, 16a, and 16b are bored and threaded axially fromthe top toreceive the hexagonal machine bolts 90. The end plates 76 of the yoke 74are L-shaped transverse plates 94 carry four vertical cylindricalcentering guides 91, two at each end. The L-shaped end plates 94 restupon approximately 36 cubic inches of chip board packing 92, at eitherside and the assembly is held in place by plates 94 and bolts 90. Thisprovides exceptional resilience and will hold, without slippage, anyincrement of pressure exerted through the pressure arm 86.

The set-up for intaglio and block printing is shown in FIGS. 2 and 7. Itis apparent that in order to make the conversion from the lithographicset-up just described, all that is necessary to do is to remove themachine bolts 90 and the yoke 74 can be lifted up and removed as a unit.To lighten the weight, the hand wheel 82 can be used to unscrew theassembly and separate the threaded stem 81 from the plunger 80. Thescrapper box 72 and the scrapper 73 itself may be lifted out as a unitand the press is then ready to receive the intaglio components. Thelarge printing roller 100 is placed in position on the press and thebearings are placed on the stub shafts 105 to form a unitary assembly.This unit is then slipped down between the posts where the bearings 10]are guided by the guides 71. When the bearings 101 and the roller 100are in position, then a spacer and cover plate 102 is placed across theposts a and 15b, 16a and 16b, and the hexagonal machine bolts 90 arereplaced in their respective positions and tightened to hold the printerroller and its bearings in position. Micrometer adjustment of pressureon the take-up bearings 101 is accomplished by the screw 103 which bearsagainst the top surface of each take-up bearings 101. The stub shaft forthe printing roller has an extension on the right hand side at 105 whichis splined to receive the roller drive sprocket 106. The sprocket 106may be used as the sprocket 55 and vice versa.

All of this presupposes that the drive mechanism for the lithographyset-up has been removed, that the sprocket 55 has been removed fromshaft 47, that the sprocket 52 has been removed from shaft 51, and thatthe chain 54 and crank 53 have also been removed.

The drive for the intaglio and block printing requires a separate post19, which is mounted at right angles vertically upward from the side bar14. Adjacent the top of the post 19, a stub shaft 108 is journalled fortotation therein and carries a small sprocket 110. This shaft andsprocket 110 are rotated by hand crank 111. The sprocket 110, and thehand crank 111 are interchangeable with sprocket 52 and crank 53. Therotation thereof is transmitted through the chain 112, and so rotatesthe large printing cylinder 100. It will be noticed that the drive forthe intaglio and block printing is through the printer roller 100 andnot as in the lithographing set-up, through the pressure rollerv45. Itis apparent that the drive can be motorized in substantially the samemanner as for lithography by attaching the counter-part chain 61 fromthe motor 58, to the small sprocket drive 108.

OPERATION In the operation of the press for lithography, the lithographstone 70, is placed on the bed 37, with the printing surface upward. Thepaper is then placed over the printing surface and then covered withblankets, sheeting and tympan. The top surface the tympan is lubricatedfor contact with the scrapper 73. The scrapper box 72 and .hence thescrapper itself 73 is lowered to contact the upper lubricated surface ofthe covering for the lithograph stone 70, by means of the hand wheel 82.The right amount of pressure required for making the print is then madeby pulling down on the pressure arm 86. The pull on the cam followersurface 88 moves the plunger 78 downwardly. The wings 89 of the plungerwork against the resiliency of the leaf springs 84. This reactive forcemakes it possible to exert pressure in very small increments without anystrain on the lever 86. The cam operated pressure system of thelithography bridge is both simple and positive. Since the camover-centers only slightly, the printmaker is not required to exert anymore force then is actually necessary in securing the precise pressure.Nor is there any danger of the pressure arm 86, being snapped upaccidentally. The pressure arm 86 provides a full linear movement at thescrapper 73, greatly facilitating the even handling of the tympan andits lubricant. When the required pressure adjustments have been made,the hand crank 53 is turned clock-wise driving the bed by means of thedrive pressure roller 45 through the yoke and under the scrapper 73,from left to right as seen in FIG. 3. One pass in this direction is allthat is necessary to make one impression. The top material above thepaper and the paper on the lithograph stone 70 are removed. Thelithograph stone is then returned to its original position by pulling upon the crank arm 66 and engaging the bed lifter rollers 67 with thebottom of the bed, freeing the bed from the drive roller 45 andpermitting the free easy return olthe bed by means of pull ing on thehand grip 44. in this manner the tedious return by turning the crank 53is eliminated.

The operation of the intaglio printing is very simple. The printingroller 100 which is the large roller with its bearings 101 is lowered inthe guides 71 to contact the' face downward on the paper. Theappropriate printing pressure is solely at the discretion of theprintmaker and is accomplished by adjusting the screw 103, at both sidesof the take-up bearing The crank 111 is turned counter clock-wise andthis rotates the printing driving drum 100 so that the printing surfaceon the bed 37 passes under the roller from left to right. The return ofthe bed to the point of beginning is accomplished in the same manner asbefore described by using the bed lifter wheels.

Since the speedy conversion and construction of this press permits theuse of large sized rollers it is not necessary to change the drivemethod to the upper roller in intaglio printing. In this manner the post19 can be eliminated entirely. No lessening of the quality results fromdriving on the lower roller, because of the use of large sized upperrollers, not possible heretofore.

We claim:

1. In an interchangable graphic press set up for lithography, a pair ofunitary complimentary side members having in co-planar arrangementV-shaped front and rear legs, horizontal side rails with inturned trackflanges and parallel upstanding hollow posts two on each side memberopen at the top and extending above and below said side rails, crossbracing between said side rails determining the width of said press,a'solid roller with its end shafts removably mounted in suitablebearings transversely of saidpress and between said posts at either sidebelow said side rails with the perimeter of said roller in levelengagement with the undersurface of a bed. a bed for said press havingattached rollers at its outer end for horizontal movement guided by saidinturned flanges and resting at its inner end on said solid roller inthe preliminary position, a yoke assembly transversely mounted at eitherside between the parallel upstanding posts and resiliently mounted withspacers, said yoke having an internally mounted eccenand between theupstanding posts.

3. In an interchangable graphic press, a pair of unitary complimentaryside members having in co-planar arrangement V-shaped front and rearlegs, horizontal side rails with inturned track flanges and parallelupstanding hollow open at the top posts two on each side memberextending above and below said side rails, cross bracing between saidside rails determining the width of said press, a solid roller with itsend shafts removably mounted in suitable bearings transversely of saidpress and between said posts at either side below said side rails withthe perimeter of said roller in level engagement with the undersurfaceof a bed, a bed for said press having attached rollers at its outer endfor horizontal movement guided by said inturned flanges and resting atits inner end on said solid roller in the preliminary position,eccentrically mounted rollers adjacent the solid roller and beneath thebed, said eccentric mounted rollers being normally out of operativeengagement with the undersurface of said bed, and means to move saideccentric rollers into operative engagement to lift the bed from contactwith said solid roller and facilitate a quick return of the bed to saidpreliminary position. =l

1. In an interchangable graphic press set up for lithography, a pair of unitary complimentary side members having in co-planar arrangement V-shaped front and rear legs, horizontal side rails with inturned tracK flanges and parallel upstanding hollow posts two on each side member open at the top and extending above and below said side rails, cross bracing between said side rails determining the width of said press, a solid roller with its end shafts removably mounted in suitable bearings transversely of said press and between said posts at either side below said side rails with the perimeter of said roller in level engagement with the undersurface of a bed, a bed for said press having attached rollers at its outer end for horizontal movement guided by said inturned flanges and resting at its inner end on said solid roller in the preliminary position, a yoke assembly transversely mounted at either side between the parallel upstanding posts and resiliently mounted with spacers, said yoke having an internally mounted eccentric for exerting great vertical pressure in small increments, a scraper box with a scraper blade mounted therebelow in precise axial transverse alignment with said solid roller, a wheel for positioning the scraper box, and speed control means for driving said solid roller.
 2. The press of claim 1 where the yoke, the scraper box and the scraper are each removably mounted on and between the upstanding posts.
 3. In an interchangable graphic press, a pair of unitary complimentary side members having in co-planar arrangement V-shaped front and rear legs, horizontal side rails with inturned track flanges and parallel upstanding hollow open at the top posts two on each side member extending above and below said side rails, cross bracing between said side rails determining the width of said press, a solid roller with its end shafts removably mounted in suitable bearings transversely of said press and between said posts at either side below said side rails with the perimeter of said roller in level engagement with the undersurface of a bed, a bed for said press having attached rollers at its outer end for horizontal movement guided by said inturned flanges and resting at its inner end on said solid roller in the preliminary position, eccentrically mounted rollers adjacent the solid roller and beneath the bed, said eccentric mounted rollers being normally out of operative engagement with the undersurface of said bed, and means to move said eccentric rollers into operative engagement to lift the bed from contact with said solid roller and facilitate a quick return of the bed to said preliminary position. 